1. Field of the Invention
This invention relates generally to an inserter device assembly and, more particularly, to an inserter assembly and a method for quickly grasping and releasing a variety of sizes of surgical implants.
2. Description of the Related Art
When invertebral (spinal) discs become herniated or rupture, they are surgically removed and replaced with bone grafts to fill the invertebral space to prevent the disc space from collapsing and to promote fusion of the adjacent vertebrae across the space. For example, in the Smith-Robinson technique for cervical fusion, the surgeon prepares the end plates of the adjacent vertebral bodies to accept a graft after the disc has been removed. The end plates are generally prepared to have parallel surfaces using a high speed burr. The surgeon sculpts the graft to fit tightly between the bone surfaces so that the graft is held by compression between the invertebral bodies. The bone graft is intended to provide structural support and promote ingrowth to achieve a solid fusion of the adjacent vertebra.
To insert the graft, surgeons have used a number of surgical instruments to grasp the graft and to position the graft between the prepared parallel surfaces. Unfortunately, the surgical instruments currently used to insert the graft have exhibited a number of shortcomings. For example, U.S. Pat. No. 5,782,830 issued to Farris discloses an actuator that slides over a jaw to close and open the jaw. One of the disadvantages here is that the pressure applied to the jaw is imprecise and the surgeon has to use both hands to hold the handle and the actuator to implant the graft. Further, the actuator is located close to the distal end of the instrument such that manipulation of the actuator may need to occur in the surgical wound were space is limited. Also, because of the large diameter of the actuator, it impedes the view of the surgical area. Another example is U.S. Pat. No. 5,443,514 issued to Steffee, which discloses an instrument 80 in FIGS. 4 through 7. Here, rotating the handle causes the jaw to open and close. However, it takes a number of turns to fully open and close the jaw which wastes valuable time when time is of the essence in surgery such as this. Also, when the handle is rotated to open the jaws the jaws are not forcibly actuated into the open position by this rotation.
Therefore, there is still a need for an insertion device that can quickly grasp and release a graft with precise pressure, allow actuation of the jaws to occur at the proximal end of the instrument and at the same time does not inhibit viewing of the surgical area.